The heart is a thick muscular organ that is composed of four chambers and located in the thorax. It is situated between both lungs in the middle compartment of the inferior mediastinum, known as the middle mediastinum.

The heart is the central organ of the cardiovascular system. It acts as a pump that maintains unidirectional blood flow through two main types of circulatory routes - systemic and pulmonary.

Overview of external heart anatomy

The heart appears somewhat pyramidal or conical-shaped, with a base (Read more!) directed upward and an apex (Read more!) pointed downward. The entire external surface area of the heart can be subdivided into five smaller surfaces that are limited by four margins.

The outer surfaces contain various grooves known as external sulci. They are created by the internal partitions of the heart. Within these external grooves pass different coronary vessels that provide arterial blood supply and venous drainage of the heart.

The heart is also connected to several larger blood vessels that arise from it or return to it, providing blood flow throughout the whole body. Because of their large diameter, they are called the great vessels of the heart.

And finally, the heart and roots of the great vessels are surrounded by a serous sac known as the pericardium or pericardial sac.

Note: The heart consists of two sides or two separate pumps - right and left. Internally, each side is divided into two chambers - an atrium and a ventricle. Both chambers are connected with each other. To summarize, the heart has four chambers - right atrium, right ventricle, left atrium and left ventricle. To learn more about the structure of the heart chambers, visit our 3D article dedicated to the internal anatomy of the heart!